Homeostasis Flashcards
What is homeostasis :
The maintenance of a stable internal environment in the body despite change in the external environment
What factors dos the body need to keep constant?
- Carbon dioxide levels
- Waste removal
- Body temperature
- Oxygen levels
- Water content
- Glucose levels
- Blood sugar levels
- Heart rate
Integrator
Compares data from receptor and stored set point data and gives instructions to effector
Negative feedback:
Mechanism that counteracts and stops any further response.
Set point
The ideal/normal value of the variable
Response:
Corrective change that brings variable back to set point
Receptor/sensor:
Sensor that detects the change in the variable
Variable:
Characteristic that is controlled
Effector:
Brings about a corrective change
Stimulus:
A change in the variable
Egestion :
Removal of waste materials that have not been inside cells (involved in cell reactions e.g. fibres in faeces)
Excretion :
The removal of waste products of cell reactions from the body (e.g. water, mineral, urea, carbon dioxide)
Carbon Dioxide comes from …
- Product of aerobic respiration
- Removed through the lungs when we breathe out
Urea comes from…
- Produced in liver when excess amino acids are broken down (liver)
- Removed by kidneys from blood and make urine, stored temporarily in bladder
Salt comes from…
Removed by kidneys ans leaves body by urine
Water comes from …
-Through skin by sweat (product of respiration)
Waste is got rid of through :
- Mouth, skin, lungs and kidneys
Waste got rid of by mouth :
- Carbon dioxide
- Water
Waste got rid of by skin :
- Water
- Salt/mineral/ions
- Urea
Waste got rid of by lungs :
- Carbon dioxide
Waste got rid of kidneys :
- Water
- Mineral/Salt/Ion
- Urea
Why is osmoregulation so important ?
Osmoregulation keeps tha blood at a steady concentration, controlling water content
When water concentration in blood is too high…
If the blood is too dilute less water is absorbed from the kidney into the blood. The water then gets into the bladder as well. After drinking a lot, a large volume of dilute urine is produced
When water concentration in blood is too low…
If the blood is too concentrated more water is absorbed back into the blood from the kidney. So if your kidney is short of water, w.f after sweating a lot, only a small amount of urine is produced.
When carbon dioxide concentration in blood is too low …
Receptors in respiratory control centre of CNS in medulla sense low concentration. Respiratory control centre of the CNS does not send nerve impulses to diaphragm and intercoastal muscles. The diaphragm mad intercostal muscles relax and breathing rate drops so carbon dioxide levels can increase
When carbon dioxide concentration in blood is too high …
The receptors in the respiratory control centre of CNS in medulla sense high carbon dioxide concentration. Respiratory control centre of CNS sends nervous impulses to diaphragm and intercoastal muscles. Diaphragm and intercoastal muscles contract. The breathing rate will increase so that carbon dioxide levels will drop.